Chibok is deep in the Boko Haram heartland of Borno State, where state security forces have little control, and details of Jonathan's visit had been closely guarded.

Instead on Friday, Jonathan will fly from the capital Abuja to Paris for a summit to discuss the Boko Haram crisis.

On Thursday Nigeria's parliament approved his request to extend by six months a state of emergency in the country's restive northeast, where according to some estimates battles between troops and Boko Haram have been responsible for more than 10,000 deaths since 2011.